ee6612 - miroprocessor and microcontroller...
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EE6612 – Microprocessors and Microcontrollers Laboratory
Department of Electrical and Electronics Engineering
EE6612 – Microprocessors and Microcontrollers Laboratory Manual
LAB MANUAL
III Year- VI Semester - Electrical and Electronics Engineering
Academic Year 2015-2016
(2013 Regulation)
EE6612 – Microprocessors and Microcontrollers Laboratory
SYLLABUS
EE6612 - MICROPROCESSORS AND MICRO CONTROLLERS LABORATORY OBJECTIVES: To provide training on programming of microprocessors and microcontrollers and understand the interface requirements. LIST OF EXPERIMENTS: 1. Simple arithmetic operations: addition / subtraction / multiplication / division. 2. Programming with control instructions:
(i) Ascending / Descending order, Maximum / Minimum of numbers (ii) Programs using Rotate instructions (iii)Hex / ASCII / BCD code conversions.
3. Interface Experiments: with 8085 (i) A/D Interfacing. & D/A Interfacing.
4. Traffic light controller. 5. I/O Port / Serial communication 6. Programming Practices with Simulators/Emulators/open source 7. Read a key,interface display 8. Demonstration of basic instructions with 8051 Micro controller execution, including:
(i) Conditional jumps, looping (ii) Calling subroutines.
9. Programming I/O Port 8051 (i) study on interface with A/D & D/A (ii (ii) study on interface with DC & AC motor .
10. Mini project development with processors.
TOTAL: 45 PERIODS OUTCOMES:
• Ability to understand and analyse, linear and digital electronic circuits. • To understand and apply computing platform and software for engineering problems.
EE6612 – Microprocessors and Microcontrollers Laboratory
LIST OF EXPERIMENTS
CYCLE I 8-bit Microprocessor
1. Simple arithmetic operations:
(a) Addition (b) subtraction (c) multiplication (d) division.
2. Ascending / Descending order, Maximum / Minimum of numbers :
(a) Ascending order (b) Descending order (c) Maximum of numbers (d) Minimum of numbers.
3. Rotate instructions:
(a) Odd and Even Number (b) Positive and Negative Number
4. Code conversion.
(a) ASCII to hexadecimal number (b) hexadecimal to ASCII (c) hexadecimal to decimal
number (d) binary to hexadecimal number and (e) hexadecimal to binary number
CYCLE II 8085 Interfacing Program 5. Interface Experiments:
(a) A/D Interfacing. (b) D/A Interfacing
6. Traffic light controller: I/O port - 8255
7. Serial Communication: 8251
8. Read a key, interface display: 8279
CYCLE III 8-bit Microcontroller
9. Demonstration of basic instructions with 8051 Micro controller execution, including:
(a) Addition (b) subtraction (c) multiplication (d) division.
10. (a) Conditional jumps, looping : Sum of elements in an array
(b) Calling subroutines : Check whether given number is Odd or Even using call option
11. Programming I/O Port :
(a) A/D Interfacing. (b) D/A Interfacing
12. Interface with DC & AC motor
13. Mini project development with processors
ADDITIONAL EXPERIMENTS
14. Interfacing 8253 Timer With 8085
15. Stepper Motor Interfacing With 8051
EE6612 – Microprocessors and Microcontrollers Laboratory
Ex. No: 1 SIMPLE ARITHMETIC OPERATIONS AIM: To write an assembly language program to add, subtract, multiply and divide the given data stored at two consecutive locations using 8085 microprocessor. a. 8 BIT DATA ADDITION: ALGORITHM:
1. Initialize memory pointer to data location. 2. Get the first number from memory in accumulator. 3. Get the second number and add it to the accumulator. 4. Store the answer at another memory location.
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOW CHART:
NO YES
START
[HL] 4500H
[A] [M]
[A] [A]+[M]
[HL] [HL]+1
STOP
[HL] [HL]+1
[M] [A]
[C] 00H
[M] [C]
[HL] [HL]+1
Is there a Carry ?
[C] [C]+1
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS OPCODE LABEL MNEMONICS OPERAND COMMENT
4100 START MVI C, 00 Clear C reg. 4101 4102 LXI H, 4500 Initialize HL reg. to
4500 4103 4104 4105 MOV A, M Transfer first data to
accumulator 4106 INX H Increment HL reg. to
point next memory Location.
4107 ADD M Add first number to acc. Content.
4108 JNC L1 Jump to location if result does not yield carry.
4109 410A 410B INR C Increment C reg. 410C L1 INX H Increment HL reg. to
point next memory Location.
410D MOV M, A Transfer the result from acc. to memory.
410E INX H Increment HL reg. to point next memory Location.
410F MOV M, C Move carry to memory 4110 HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
b. 8 BIT DATA SUBTRACTION ALGORITHM:
1. Initialize memory pointer to data location. 2. Get the first number from memory in accumulator. 3. Get the second number and subtract from the accumulator. 4. If the result yields a borrow, the content of the acc. is complemented and 01H is added
to it (2’s complement). A register is cleared and the content of that reg. is incremented in case there is a borrow. If there is no borrow the content of the acc. is directly taken as the result.
5. Store the answer at next memory location.
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOW CHART: NO YES
START
[HL] 4500H
[A] [M]
Is there a Borrow?
[A] [A]-[M]
[HL] [HL]+1
[C] 00H
[C] [C]+1
STOP
[HL] [HL]+1
[M] [A]
[M] [C]
[HL] [HL]+1
Complement [A] Add 01H to [A]
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS OPCODE LABEL MNEMONICS OPERAND COMMENT
4100 START MVI C, 00 Clear C reg. 4101 4102 LXI H, 4500 Initialize HL reg. to
4500 4103 4104 4105 MOV A, M Transfer first data to
accumulator 4106 INX H Increment HL reg. to
point next mem. Location.
4107 SUB M Subtract first number from acc. Content.
4108 JNC L1 Jump to location if result does not yield borrow.
4109 410A 410B INR C Increment C reg. 410C CMA Complement the Acc.
content 410D ADI 01H Add 01H to content of
acc. 410E 410F L1 INX H Increment HL reg. to
point next mem. Location.
4110 MOV M, A Transfer the result from acc. to memory.
4111 INX H Increment HL reg. to point next mem. Location.
4112 MOV M, C Move carry to mem. 4113 HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
c. 8 BIT DATA MULTIPLICATION: ALGORITHM: LOGIC: Multiplication can be done by repeated addition.
1. Initialize memory pointer to data location. 2. Move multiplicand to a register. 3. Move the multiplier to another register. 4. Clear the accumulator. 5. Add multiplicand to accumulator 6. Decrement multiplier 7. Repeat step 5 till multiplier comes to zero. 8. The result, which is in the accumulator, is stored in a memory location.
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOW CHART: NO YES NO YES
[HL] ←4500
B ← M
A ← 00
C ← 00
Is there any carry
C ← C+1
B ← B-1
[A] ← [A] +[M]
[HL] ← [HL]+1
IS B=0
A
START
EE6612 – Microprocessors and Microcontrollers Laboratory
A
STOP
[HL] [HL]+1
[M] [A]
[M] [C]
[HL] [HL]+1
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS OPCODE LABEL MNEMONICS OPERAND COMMENT
4100 START LXI H, 4500 Initialize HL reg. to 4500 Transfer first data to reg. B
4101 4102 4103 MOV B, M
4104 INX H Increment HL reg. to point next mem. Location.
4105 MVI A, 00H Clear the acc. 4106
4107 MVI C, 00H Clear C reg for carry
4108
4109 L1 ADD M Add multiplicand multiplier times.
410A JNC NEXT Jump to NEXT if there is no carry 410B
410C 410D INR C Increment C reg 410E NEXT DCR B Decrement B reg 410F JNZ L1 Jump to L1 if B is not
zero. 4110 4111 4112 INX H Increment HL reg. to
point next mem. Location.
4113 MOV M, A Transfer the result from acc. to memory.
4114 INX H Increment HL reg. to point next mem. Location.
4115 MOV M, C Transfer the result from C reg. to memory.
4116 HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
d. 8 BIT DIVISION: ALGORITHM: LOGIC: Division is done using the method Repeated subtraction.
1. Load Divisor and Dividend 2. Subtract divisor from dividend 3. Count the number of times of subtraction which equals the quotient 4. Stop subtraction when the dividend is less than the divisor .The dividend now becomes
the remainder. Otherwise go to step 2. 5. Stop the program execution.
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOWCHART: YES
Yes
No
B ← 00
M ← A-M
[B] ← [B] +1
IS A<0
A ← A+ M
B ← B-1
[HL] ←4500
A ← M
[HL] ← [HL]+1
START
STOP
[HL] [HL]+1
[M] [A]
[M] [B]
[HL] [HL]+1
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS OPCODE LABEL MNEMONICS OPERAND COMMENTS
4100 MVI B,00 Clear B reg for quotient4101 4102 LXI H,4500 Initialize HL reg. to
4500H 4103 4104 4105 MOV A,M Transfer dividend to
acc. 4106 INX H Increment HL reg. to
point next mem. Location.
4107 LOOP SUB M Subtract divisor from dividend
4108 INR B Increment B reg 4109 JNC LOOP Jump to LOOP if
result does not yield borrow
410A 410B 410C ADD M Add divisor to acc. 410D DCR B Decrement B reg 410E INX H Increment HL reg. to
point next mem. Location.
410F MOV M,A Transfer the remainder from acc. to memory.
4110 INX H Increment HL reg. to point next mem. Location.
4111 MOV M,B Transfer the quotient from B reg. to memory.
4112 HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
OBSERVATION: ADDITION:
S.NO INPUT OUTPUT ADDRESS DATA ADDRESS DATA
1 4500 4502 4501 4503
2 4500 4502 4501 4503
SUBTRACTION:
S.NO INPUT OUTPUT ADDRESS DATA ADDRESS DATA
1 4500 4502 4501 4503
2 4500 4502 4501 4503
MULTIPLICATION:
S.NO INPUT OUTPUT ADDRESS DATA ADDRESS DATA
1 4500 4502 4501 4503
2 4500 4502 4501 4503
DIVISION:
S.NO INPUT OUTPUT ADDRESS DATA ADDRESS DATA
1 4500 4502 4501 4503
2 4500 4502 4501 4503
EE6612 – Microprocessors and Microcontrollers Laboratory
RESULT:
Thus the addition, subtraction, multiplication and division of two numbers was
performed using the 8085 microprocessor.
EE6612 – Microprocessors and Microcontrollers Laboratory
Ex. No: 2 Ascending / Descending order, Maximum / Minimum of numbers AIM: To write an assembly language program to arrange an array of data in ascending and descending order and to find the smallest and largest data among the array. a. ASCENDING ORDER
ALGORITHM: 1. Get the numbers to be sorted from the memory locations. 2. Compare the first two numbers and if the first number is larger than second then I interchange the number. 3. If the first number is smaller, go to step 4 4. Repeat steps 2 and 3 until the numbers are in required order
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOWCHART:
Yes
No
[HL] 4200H [C] [HL]
[C] [C] -1
[HL] 4201H
[HL [HL] + 1
Is [A] < [HL]?
[B] [HL]
[HL] [A]
[HL] [HL] - 1
[HL] [B]
[HL] [HL] + 1
[D] [D] – 01 H
A
[D] [C]
START
[A] [HL]
EE6612 – Microprocessors and Microcontrollers Laboratory
Yes
Yes
No
No
IS [D] = 0?
A
[C] [C]-1
IS [C] = 0?
STOP
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS OPC
ODE LABEL MNEMONICS OPERA
ND COMMENTS
4100 LXI H,4200 Set pointer for array 4101 4102 4103 MOV C,M Load the Count 4104 DCR C Decrement Count 4105 LOOP 3 MOV D,C Transfer data from C to
D 4106 LXI H,4201 Load data from 4201 4107 4108 4109 LOOP2 MOV A,M Copy content of M to A 410A INX H Increment HL reg. to
point next memory location
410B CMP M Compare M & A 410C JC LOOP1 If A is lesser than M
then go to loop1 410D 410E 410F MOV B,M Transfer data from M to
D reg 4110 MOV M,A Transfer data from acc
to M 4111 DCX H Decrement HL pair 4112 MOV M,B Transfer data from B to
M 4113 INX H Increment HL pair 4114 LOOP1 DCR D Decrement D reg 4115 JNZ LOOP2 If D is not zero go to
loop2 4116 4117 4118 DCR C Decrement C reg 4119 JNZ LOOP3 If C is not Zero go to
loop3 411A 411B 411C HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
b. DESCENDING ORDER
ALGORITHM: 1. Get the numbers to be sorted from the memory locations. 2. Compare the first two numbers and if the first number is smaller than second then I interchange the number. 3. If the first number is larger, go to step 4 4. Repeat steps 2 and 3 until the numbers are in required order
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOWCHART:
No
Yes
[HL] 4200H [C] [HL]
[C] [C] -1
[HL] 4201H
[HL [HL] + 1
Is [A] < [HL]?
[B] [HL]
[HL] [A]
[HL] [HL] - 1
[HL] [B]
[HL] [HL] + 1
[D] [D] – 01 H
A
[D] [C]
START
[A] [HL]
EE6612 – Microprocessors and Microcontrollers Laboratory
Yes
Yes
No
No
IS [D] = 0?
A
[C] [C]-1
IS [C] = 0?
STOP
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS OPC
ODE LABEL MNEMONICS OPERA
ND COMMENTS
4100 LXI H,4200 Set pointer for array 4101 4102 4103 MOV C,M Load the Count 4104 DCR C Decrement Count 4105 LOOP 3 MOV D,C Transfer data from C to
D 4106 LXI H,4201 Load data from 4201 4107 4108 4109 LOOP2 MOV A,M Copy content of M to A 410A INX H Increment HL reg. to
point next memory location
410B CMP M Compare M & A 410C JNC LOOP1 If A is lesser than M
then go to loop1 410D 410E 410F MOV B,M Transfer data from M to
D reg 4110 MOV M,A Transfer data from acc
to M 4111 DCX H Decrement HL pair 4112 MOV M,B Transfer data from B to
M 4113 INX H Increment HL pair 4114 LOOP1 DCR D Decrement D reg 4115 JNZ LOOP2 If D is not zero go to
loop2 4116 4117 4118 DCR C Decrement C reg 4119 JNZ LOOP3 If C is not Zero go to
loop3 411A 411B 411C HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
c. LARGEST ELEMENT IN AN ARRAY
ALGORITHM:
1. Place all the elements of an array in the consecutive memory locations.
2. Fetch the first element from the memory location and load it in the accumulator.
3. Initialize a counter (register) with the total number of elements in an array.
4. Decrement the counter by 1.
5. Increment the memory pointer to point to the next element.
6. Compare the accumulator content with the memory content (next
element).
7. If the accumulator content is smaller, then move the memory content
(largest element) to the accumulator. Else continue.
8. Decrement the counter by 1.
9. Repeat steps 5 to 8 until the counter reaches zero
10. Store the result (accumulator content) in the specified memory location.
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOW CHART:
NO YES NO YES
[B] 04H
[HL] [4200H]
[A] [HL]
[HL [HL] + 1
IS [A] < [HL]?
[A] [HL]
[4205] [A]
START
[B] [B]-1
IS [B] = 0?
STOP
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM:
ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPER AND
COMMENTS
4101 LXI H,4200 Initialize HL reg. to 4200H 4102
4103 4104 MVI B,04 Initialize B reg with no. of
comparisons(n-1) 4105 4106 MOV A,M Transfer first data to acc. 4107 LOOP1 INX H Increment HL reg. to point
next memory location 4108 CMP M Compare M & A 4109 JNC LOOP If A is greater than M then go
to loop 410A 410B 410C MOV A,M Transfer data from M to A reg 410D LOOP DCR B Decrement B reg 410E JNZ LOOP1 If B is not Zero go to loop1 410F 4110 4111 STA 4205 Store the result in a memory
location. 4112 4113 4114 HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
d. SMALLEST ELEMENT IN AN ARRAY
ALGORITHM:
1. Place all the elements of an array in the consecutive memory locations.
2. Fetch the first element from the memory location and load it in the accumulator.
3. Initialize a counter (register) with the total number of elements in an array.
4. Decrement the counter by 1.
5. Increment the memory pointer to point to the next element.
6. Compare the accumulator content with the memory content (next
element).
7. If the accumulator content is smaller, then move the memory content
(largest element) to the accumulator. Else continue.
8. Decrement the counter by 1.
9. Repeat steps 5 to 8 until the counter reaches zero
10. Store the result (accumulator content) in the specified memory location.
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOW CHART:
YES NO NO YES
[B] 04H
[HL] [4200H]
[A] [HL]
[HL [HL] + 1
IS [A] < [HL]?
[A] [HL]
[4205] [A]
START
[B] [B]-1
IS [B] = 0?
STOP
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM:
ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPER AND
COMMENTS
4101 LXI H,4200 Initialize HL reg. to 4200H 4102
4103 4104 MVI B,04 Initialize B reg with no. of
comparisons(n-1) 4105 4106 MOV A,M Transfer first data to acc. 4107 LOOP1 INX H Increment HL reg. to point
next memory location 4108 CMP M Compare M & A 4109 JC LOOP If A is lesser than M then go
to loop 410A 410B 410C MOV A,M Transfer data from M to A reg 410D LOOP DCR B Decrement B reg 410E JNZ LOOP1 If B is not Zero go to loop1 410F 4110 4111 STA 4205 Store the result in a memory
location. 4112 4113 4114 HLT Stop the program
EE6612 – Microprocessors and Microcontrollers Laboratory
OBSERVATION: A. ASCENDING ORDER
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4200 4200 4201 4201 4202 4202 4203 4203 4204 4204
B. DESCENDING ORDER
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4200 4200 4201 4201 4202 4202 4203 4203 4204 4204
EE6612 – Microprocessors and Microcontrollers Laboratory
C. SMALLEST ELEMENT
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4200 4201 4202 4205 4203 4204
D. LARGEST ELEMENT
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4200 4201 4202 4205 4203 4204
EE6612 – Microprocessors and Microcontrollers Laboratory
RESULT:
Thus the sorting operations of arranging an array in ascending, descending order and
the largest and smallest element were found using the 8085 microprocessor.
EE6612 – Microprocessors and Microcontrollers Laboratory
Ex. No: 3 FIND THE NUMBER OF EVEN AND ODD NUMBER IN A BLOCK OF DATA
AIM:
To find the number of even and odd number, and number of positive and negative
numbers in a block of data.
a. Odd and Even Number
ALGORITHM:
1. Start.
2. Load the given data.
3. Clear the data in accumulator.
4. Move the content of accumulator to D and B register.
5. Increment HL register pair and move the content of memory to accumulator.
6. Rotate the obtain data in the form of RAR.
7. If carry occur increment B else increment D.
8. Decrement C, if C ≠0 go to step 5. Else increment HL pair.
9. Move the content of D to memory and increment HL pair and move the content B to
memory.
10. Stop.
EE6612 – Microprocessors and Microcontrollers Laboratory
Yes
No
No Yes
[A] 00H
[HL] [4200H] [C] [HL]
[B] [A] [D] [A]
[HL [HL] + 1 [A] [HL]
Is CY=1
START
[C] [C]-1
Is [C] = 0?
STOP
Rotate the A right through carry
[B] [B]+1, for odd [D] [D]+1, for even
[HL] [HL]+1, [HL] D
[HL] [HL]+1, [HL] B
EE6612 – Microprocessors and Microcontrollers Laboratory
ADDRE SS
OPCO DE
LABEL MNEM ONICS
OPER AND
COMMENTS
4100 LXI H,4200 Load the number of data 4101 4102 4103 MOV C, M Move M to C 4104 XRA A Exclusive OR reg A 4105 MOV D, A Move A to D 4106 MOV B, A Move A to B 4107 L3 INX H H Increment H 4108 MOV A,M Move M to A 4109
RAR Rotate right through
carry 410A JNC L1 Jump no carry 410B 410C 410D INR D Increment D 410E JMP L2 Jump to L2 410F 4110 4111 L1 INR B Increment B 4112 L2 DCR C Decrement C 4113 JNZ L3 Jump non Zero 4114 4115 4116 INX H Increment H 4117 LOOP MOV M, D Move D to M 4118 INX H H Increment H 4119 MOV M, B Move B to M 411A HLT Halt the program
EE6612 – Microprocessors and Microcontrollers Laboratory
b. Positive and Negative Number
ALGORITHM:
1. Start.
2. Load the given data.
3. Clear the data in accumulator.
4. Move the content of accumulator to D and B register.
5. Increment HL register pair and move the content of memory to accumulator.
6. Rotate the obtain data in the form of RAL.
7. If carry occur increment B else increment D.
8. Decrement C, if C ≠0 go to step 5. Else increment HL pair.
9. Move the content of D to memory and increment HL pair and move the content B to
memory.
10. Stop.
EE6612 – Microprocessors and Microcontrollers Laboratory
Yes
No
No Yes
[A] 00H
[HL] [4200H] [C] [HL]
[B] [A] [D] [A]
[HL [HL] + 1 [A] [HL]
Is CY=1
START
[C] [C]-1
Is [C] = 0?
STOP
Rotate the A left through carry
[B] [B]+1, negative [D] [D]+1, positive
[HL] [HL]+1, [HL] D
[HL] [HL]+1, [HL] B
EE6612 – Microprocessors and Microcontrollers Laboratory
ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPER AND
COMMENTS
4100 LXI H,4200 Load the number of data 4101 4102 4103 MOV C, M Move M to C 4104 XRA A Exclusive OR reg A 4105 MOV D, A Move A to D 4106 MOV B, A Move A to B 4107 L3 INX H H Increment H 4108 MOV A,M Move M to A 4109 RAL Rotate left through carry 410A JNC L1 Jump no carry 410B 410C 410D INR D Increment D 410E JMP L2 Jump to L2 410F 4110 4111 L1 INR B Increment B 4112 L2 DCR C Decrement C 4113 JNZ L3 Jump non Zero 4114 4115 4116 INX H Increment H 4117 LOOP MOV M, D Move D to M 4118 INX H H Increment H 4119 MOV M, B Move B to M 411A HLT Halt the program
EE6612 – Microprocessors and Microcontrollers Laboratory
Observation a. Odd and even number
INPUT: OUTPUT:
4200 = 04 4205=03 (Odd numbers)
4201= 01 4206=01 (Even numbers)
4202 = 05
4203 = 03
4204 = 04 b. Positive and negative number
INPUT: OUTPUT:
4200 = 04 4205=01 (Negative numbers)
4201= 01 4206=03 (Positive numbers)
4202 = F5
4203 = 03
4204 = 74 RESULT:
Thus the number of even and odd number, and positive and negative number has been found from the given number of list.
EE6612 – Microprocessors and Microcontrollers Laboratory
Ex. No: 4 CODE CONVERSIONS AIM: To write an assembly language program to perform the conversions of ASCII to hexadecimal number, hexadecimal to ASCII, hexadecimal to decimal number, binary to hexadecimal number and hexadecimal to binary number. a.ASCII TO HEXADECIMAL ALGORITHM:
1. Start the program 2. Load the data from address 4200 to A 3. Move data from accumulator to C 4. Move data from M to HL pair to accumulator 5. Subtract the data 30 from A 6. Decrement content of register 7. Stop the program if C is zero 8. Jump to Step 5 9. End the program
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOWCHART: YES NO
Start
Set the ASCII value
Check for
Carry?
Decrement the register content
Subtract 30 from A
Subtract 07 from A
Store the hex value
Stop
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPER AND
COMMENTS
4100 LDA H,4200 Load data 4200 to A 4101 4102 4103 MOV C,A Move data from A to C 4104 LXI H,4201 Load address 4201 in HL 4105 4106 4107 LXI D,4301 Load address 4301 in DF 4108 4109 410A LOOP 1 MOV A,M Move data from M to A 410B SUI 30 Subtract 30 from A 410C 410D STAX D Store data from
accumulator to DE 410E DCR C Decrement from C
register 410F JZ LOOP Stop program if C is 0 4110 4111 4112 INX H Increment HL register
pair 4113 INX D Increment DE register
pair 4114 JMP LOOP 1 Jump to 410A 4115 4116 4117 LOOP HLT Stop
EE6612 – Microprocessors and Microcontrollers Laboratory
b. HEXADECIMAL TO ASCII ALGORITHM:
1. Start the program 2. Load the data from address 4200 to A 3. Move data from accumulator to C 4. Move data from M to HL pair to accumulator 5. Add the data 30 to A 6. Decrement content of register 7. Stop the program if C is zero 8. Jump to Step 5 9. End the program
EE6612 – Microprocessors and Microcontrollers Laboratory
FLOWCHART: YES NO
Set the ASCII value
Check for
Carry?
Decrement the register content
Add 30 to A
Store the decimal value
Stop
Start
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPER AND
COMMENTS
4100 LDA H,4200 Load data 4200 to A 4101 4102 4103 MOV C,A Move data from A to C 4104 LXI H,4201 Load address 4201 in HL 4105 4106 4107 LXI D,4301 Load address 4301 in DF 4108 4109 410A LOOP 1 MOV A,M Move data from M to A 410B ADI 30 Subtract 30 from A 410C 410D STAX D Store data from
accumulator to DE 410E DCR C Decrement from C
register 410F JZ LOOP Stop program if C is 0 4110 4111 4112 INX H Increment HL register
pair 4113 INX D Increment DE register
pair 4114 JMP LOOP 1 Jump to 410A 4115 4116 4117 LOOP HLT Stop
EE6612 – Microprocessors and Microcontrollers Laboratory
c. HEXADECIMAL TO BINARY ALGORITHM:
1. Start the program 2. Move the content of memory to accumulator 3. Move data 0B o register B 4. Increment the content of HL register pair 5. Rotate the accumulator right 6. Jump to the specified address if carry generated 7. Move 00 to memory 8. Jump to specified address if there is no zero 9. Move 01 to memory 10. Jump to specified address if there is no zero 11. End the program
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FLOWCHART: YES
NO NO YES
Load address in HL pair
Check for Carry?
Initialize counter B to 08
Move data from M to A
Stop
Start
Increments HL register pair
Rotate accumulator right
Decrement B register
Move data from 01 to M
Move data from 00 to M
If B=0?
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PROGRAM: ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPERAND COMMENTS
4100 LXI H,4200 Load address in HL pair 4101 4102 4103 MOV A,M Move content of M to A 4104 MVI B, 08 Move 0B to register pair 4105 4106 L3 INX H Increment the content of
HL pair 4107 RRC Rotate accumulator right 4108 JC L1 Jump to specified address
if carry 4109 410A 410B MVI M, 00 Move 00 to M 410C JMP L2 Decrement B register 410D 410E 410F L1 MVI M, 01 Move 01 to M 4110 4111 L2 DCR B Decrement B by 1 4112 JNZ L3 Jump to the specified
address if no zero 4113 4114 4115 HLT Stop the program
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d. BINARY TO HEXADECIMAL ALGORITHM:
1. Start the program 2. Load the address in HL pair 3. Move the content of memory to accumulator 4. Add the content of accumulator with previous content of accumulator 5. Move the content of B to accumulator 6. Add the content of accumulator with previous content of accumulator 7. Repeat step 6 8. Add B with accumulator content 9. Increment H by 1 10. Move content of M to A 11. End the program
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FLOWCHART:
Load address in HL pair
Add content of A to register B
Move data from M to A
Start
Add content of A with itself
Add content of A to register B
Increment HL reg pair content
Add content of M with accumulator
Increment HL reg pair
Move content of M to accumulator
Stop
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PROGRAM: ADDRE
SS OPCO DE
LABEL MNEM ONICS
OPERAND COMMENTS
4100 LXI H,4150 Load address in HL pair 4101 4102 4103 MOV M,A Move content of A to M 4104 ADD A Add A content with
previous content of A 4105 MOV B, A Move the content from
A to B 4106 ADD A Add A content with
previous content of A 4107 ADD B Add B content with A 4108 INX H Increment H by 1 4109 ADD M Add M content with A 410A INX H Increment H by 1 410B MOV M, A Move content of A to M 410C HLT Stop the program
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e. HEXADECIMAL TO DECIMAL ALGORITHM:
1. Start the program 2. Load the address in HL pair 3. Move the content from HL to A 4. Subtract 64 from A 5. Increment BC pair 6. Jump to address 4207 7. Subtract 0A from A 8. Increment HL pair 9. Rotate accumulator left 10. Increment HL pair 11. End the program
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FLOWCHART: YES NO
NO YES
Load address in HL pair
Check Carry?
Clear accumulator
Initialize D register
Stop
Start
Move HL to C register
Add 01 with A
Store A in 4150 H
Move D to accumulator
Store A in 4151 H
Adjust A to BCD
Increment C register
Increment D register
Check Carry?
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PROGRAM: ADDRE
SS OPCO
DE LABEL MNEM
ONICS OPER AND
COMMENTS
4100 LXI H, 4150 Load data from 4150 to HL pair 4101 4102 4103 LXI B, 0000 Load data from address to BC 4104 4105 4106 MOV A, M Move the content from HL to A 4107 L4 SUI 64 Subtract 64 from A 4108 4109 JC L1 Stop if A has carry 410A 410B 410C INR B Increment BC 410D JMP L4 Jump to specified address 410E 410F 4110 L1 ADI 64 Add 64 to A 4111 4112 L3 SUI 0A Subtract 0A from A 4113 4114 JC L2 Stop if A has carry 4115 4116 4117 INR C Increment HL 4118 L2 JNC L3 Stop if A has no carry 4119 411A 411B ADI 0A Add 0A to A 411D INX H Increment HL 411E MOV M, B Move B to M 411F MOV B, A Move A to B 4120 MOV A, B Move B to A 4121 RLC Rotate accumulator 4122 RLC Rotate accumulator 4123 RLC Rotate accumulator 4124 RLC Rotate accumulator 4125 ADD B Add B to A
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4126 INX H Increment H by 1 4127 MOV M, A Move content of A to M 4128 HLT Stop the program
OBSERVATION: a. ASCII TO HEXADECIMAL
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4201 4301 b. HEXADECIMAL TO ASCII
INPUT OUTPUT
MEMORY LOCATION
DATA MEMORY LOCATION
DATA
4201 4301 c. HEXADECIMAL TO BINARY
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA MEMORY
LOCATIONDATA
4200
4200 4204 4201 4205 4202 4206 4203 4207
d. BINARY TO HEXADECIMAL
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4150 4152
4151
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e. HEXADECIMAL TO DECIMAL
INPUT OUTPUT MEMORY
LOCATION DATA MEMORY
LOCATION DATA
4150 4152
4151
RESULT:
Thus the assembly language programs for various code conversions are executed using
8085 microprocessor.
EE6612 – Microprocessors and Microcontrollers Laboratory
EX.No:5 INTERFACING A/D AND D/A CONVERTER WITH 8085 AIM: To write an assembly language program to convert an analog signal into a digital signal and a digital signal into an analog signal using an ADC interfacing and DAC interfacing respectively. a. ADC INTERFACING WITH 8085 APPARATUS REQUIRED:
SL.NO ITEM SPECIFICATION QUANTITY 1 Microprocessor kit 8085,Vi Microsystems 1 2 Power supply +5 V dc 1 3 ADC Interface board Vi Microsystems 1
PROBLEM STATEMENT: To program starts from memory location 4100H. The program is executed for various values of analog voltage which are set with the help of a potentiometer. The LED display is verified with the digital value that is stored in the memory location 4150H. THEORY: An ADC usually has two additional control lines: the SOC input to tell the ADC when to start the conversion and the EOC output to announce when the conversion is complete. The following program initiates the conversion process, checks the EOC pin of ADC 0419 as to whether the conversion is over and then inputs the data to the processor. It also instructs the processor to store the converted digital data at RAM 4200H. ALGORITHM:
1. Select the channel and latch the address. 2. Send the start conversion pulse. 3. Read EOC signal. 4. If EOC =1 continue else go to step (3) 5. Read the digital output. 6. Store it in a memory location.
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PROGRAM: ADDRESS OPCO
DE LABEL MNEMON ICS OPERA
ND COMMENTS
4100 MVI A, 10 Select channel 0 and to make accumulator low
4101 4102 OUT C8 Output the data 4103 4104 MVI A, 18 Make accumulator high 4105 4106 OUT C8 Display the data 4107 4108 MVI A, 01 Make 01 to accumulator 4109 410A OUT D0 Display the data 410B 410C XRA XOR with accumulator 410D XRA XOR with accumulator 410E XRA XOR with accumulator 410F MVI A, 00 Make 00 to accumulator 4110 4111 OUT D0 Load D0 in output port 4112 4113 LOOP IN D8 4114 4115 ANI 01 Do and operation directly 4116 4117 CPI 01 Compare with accumulator 4118 4119 JNZ LOOP Jump to specified address 411A 411B 411C IN C0 411D 411E STA 4150 Store the data 411F 4120 4121 HLT End the program
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ADC- CIRCUIT:
SOC JUMPER SELECTION:
J2: SOC Jumper selection J5: Channel selection
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OBSERVATION
ANALOG VOLTAGE DIGITAL DATA ON LED DISPLAY
HEX CODE IN LOCATION 4150
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b. DAC INTERFACING WITH 8085 APPARATUS REQUIRED:
SL.NO ITEM SPECIFICATION QUANTITY 1 Microprocessor kit 8085,Vi Microsystems 1 2 Power supply +5 V dc 1 3 DAC Interface board Vi Microsystems 1
SOFTWARE EXAMPLES The following examples illustrate how to control the DAC using 8085 and generate sine wave, saw tooth wave by means of software. (a) SQUARE WAVE GENERATION:
The basic idea behind the generation of waveforms is the continuous generation of
Analog output of DAC. With 00(HEX) as input to DAC2, the analog output is -5V. Similarly, with FF (Hex) as input, the output is +5V. Outputting digital data 00 and FF at regular intervals, to DAC2, results in a square wave of amplitude I5 Volts
ALGORITHM:
1. Load the initial value (00) to Accumulator and move it to DAC. 2. Call the delay program 3. Load the final value (FF) to accumulator and move it to DAC. 4. Call the delay program. 5. Repeat steps 2 to 5.
PROGRAM:
ADDRESS OPCO
DE LABEL MNEMON ICS OPERAND COMMENT
4100 START MVI A, 00 Move 00 to A register 4101 4102 OUT C8 Load C8 to output port 4103 4104 CALL DELAY Call delay program 4107 MVI A, FF Load FF to B register 4109 OUT C8 410B CALL DELAY
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410E JMP START START Jump to start of address 4112 DELAY MVI B, 05 Move 05 to B register 4114 L1 MVI C, FF Move FF to C register 4116 L2 DCR C Decrement C 4117 JNZ L2 Jump to L2 if no zero 411A DCR B Decrement B register 411B JNZ L1 Jump to L1 if no zero 411E RET
Execute the program and using a CRO, verify that the waveform at the DAC2 output is a square-wave. Modify the frequency of the square-wave, by varying the time delay.
(b) SAW TOOTH GENERATION: ALGORITHM: 1. Load the initial value (00) to Accumulator 2. Move the accumulator content to DAC. 3. Increment the accumulator content by 1. 4. Repeat steps 3 and 4. Output digital data from 00 to FF constant steps of 01 to DAC1 repeat this sequence again and again. As a result a saw – tooth wave will be generated at DAC1 output. PROGRAM: ADDRESS OPCO
DE LABEL MNEMON ICS OPERAN
D COMMENT
4100 START MVI A, 00 Load 00 to accumulator 4102 L1 OUT C0 Load CO in output port 4104 INR A Increment A register 4105 JNZ L1 Jump to L1 if no zero 4108 JMP START Go to START
unconditionally
(c) TRIANGULAR WAVE GENERATION: ALGORITHM:
1. Load the initial value (00) to Accumulator. 2. Move the accumulator content to DAC 3. Increment the accumulator content by 1. 4. If accumulator content is zero proceed to next step. Else go to step 3. 5. Load value (FF) to accumulator. 6. Move the accumulator content to DAC.
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7. Decrement the accumulator content by 1. 8. If accumulator content is zero go to step 2. Else go to step 2. The following program will generate a triangular wave at DAC2 output. PROGRAM: ADDRESS OPCO
DE LABEL MNEMON ICS OPERA
ND COMMENT
4100 START MVI L, 00 Move 00 to L register 4102 L1 MOV A, L Load L to a register 4103 OUT C8 Load c8 to output port 4105 INR L Increment L register 4106 JNZ L1 Jump to L1 if no zero 4109 MVI L, FF Load FF to L register 410B L2 MOV A, L Move L to a register 410C OUT C8 Load C8 to output port 410E DCR L Decrement L register 410F JNZ L2 Jump to L2 if no zero 4112 JMP START Go to START unconditionally
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OBSERVATION: WAVE FORMS AMPLITUDE TIME PERIOD Square waveform Saw tooth waveform Triangular waveform Result: Thus the conversion of an analog signal into a digital signal and a digital signal into an analog signal was done using interfacing of ADC and DAC respectively with 8085.
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EX.No:6 TRAFFIC LIGHT CONTROLLERS WITH 8085 AIM To write an assembly language program to simulate the traffic light at an intersection using a traffic light interface. APPARATUS REQUIRED: SL.NO ITEM SPECIFICATION QUANTITY 1 Microprocessor kit 4185,Vi Microsystems 1 2 Power supply +5 V dc 1 3 Traffic light interface kit Vi Microsystems 1
ALGORITHM:
1. Initialize the ports. 2. Initialize the memory content, with some address to the data. 3. Read data for each sequence from the memory and display it through the ports. 4. After completing all the sequences, repeat from step2.
A SAMPLE SEQUENCE: 1. (a) Vehicles from south can go to straight or left. (b) Vehicles from west can cross the road. (c) Each pedestrian can cross the road. (d) Vehicles from east no movement. (e) Vehicles from north can go only straight. 2. All ambers are ON, indicating the change of sequence.
3. (a) Vehicles from east can go straight and left. (b) Vehicles from south can go only left. (c) North pedestrian can cross the road. (d) Vehicles from north, no movement. (e) Vehicles from west can go only straight.
4. All ambers are ON, indicating the change of sequence. 5. (a) Vehicles from north can go straight and left.
(b) Vehicles from east can go only left. (c) West pedestrian can cross the road. (d) Vehicles from west, no movement. (e) Vehicles from south can go only straight.
6. All ambers are ON, indicating the change of sequence.
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7. (a) Vehicles from west can go straight and left.
(b) Vehicles from north can go only left. (c) South pedestrian can cross the road. (d) Vehicles from south, no movement. (e) Vehicles from east can go only straight.
8. All ambers are ON, indicating the change of sequence. 9. (a) All vehicles from all directions no movement. (b) All pedestrian can cross the road. BIT ALLOCATION: BIT LED BIT LED BIT LED
PA0 SOUTH LEFT PB0 NORTH LEFT PC0 WEST STRAIGHT PA1 SOUTH RIGHT PB1 NORTH RIGHT PC1 NORTH STRAIGHT PA2 SOUTH AMBER PB2 NORTH AMBER PC2 EAST STRAIGHT PA3 SOUTH RED PB3 NORTH RED PC3 SOUTH STRAIGHT PA4 EAST LEFT PB4 WEST LEFT PC4 NORTH PD PA5 EAST RIGHT PB5 WEST RIGHT PC5 WEST PD PA6 EAST AMBER PB6 WEST AMBER PC6 SOUTH PD PA7 EAST RED PB7 WEST RED PC7 EAST PD
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PATH REPRESENTATION:
CONTROL ----- 0F (FOR 8255 PPI) PORT A ----- 0C PORT B ----- 0D PORT C ----- 0E
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PROGRAM: ADDRESS
OPCODE LABEL MNEMON ICS
OPERAND
COMMENT
4100 3E MVI A, 41 Move 41H immediately to accumulator
4102 D3 OUT 0F Output contents of accumulator to OF port
4104 REPEAT LXI H,DATA_SQ
Load address 417B to HL register
4107 11 LXI D,DATA_
E Load address 4187 to DE register
410A CD CALL OUT Call out address 4142 410D EB XCHG Exchange contents of HL
with DE pair 410E 7E MOV A, M Move M content to
accumulator 410F D3 OUT 0D Load port A into output port 4111 CD CALL DELAY1 Call delay address 4114 EB XCHG Exchange content of HL
with DE pair 4115 13 INX D Increment the content of D 4116 23 INX H Increment the content of H 4117 CD CALL OUT Call out the address 411A EB XCHG Exchange content of HL
with DE pair 411B 7E MOV A, M Move M content to
accumulator 411C D3 OUT 0D Load port B into output port 411E CD CALL DELAY1 Call DELAY address 4121 EB XCHG Exchange content of HL
with DE pair 4122 13 INX D Increment D register 4123 23 INX H Increment H register 4124 CD CALL OUT Call specified address 4127 EB XCHG Exchange content of HL
with DE pair 4128 7E MOV A, M Move M content to
accumulator 4129 D3 OUT 0E Load port C into output port
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412B CD CALL DELAY1 Call DELAY address 412E EB XCHG Exchange content of HL
with DE pair 412F 13 INX D Increment D register 4130 23 INX H Increment H register 4131 CD CALL OUT Call specified address 4134 EB XCHG Exchange content of HL
with DE pair 4135 7E MOV A, M Move M content to
accumulator 4136 D3 OUT 0E Load port C into output port 4138 23 INX H Increment H register 4139 7E MOV A, M Move M content to
accumulator 413A D3 OUT 0C Load port A into output port 413C CD CALL DELAY1 Call DELAY address 413F C3 JMP REPEAT Jump to specified address 4142 7E OUT MOV A, M Move M content to
accumulator 4143 D3 OUT 0E Load port C into output port 4145 23 INX H Increment H register 4146 7E MOV A, M Move M content to
accumulator 4147 D3 OUT 0D Load port B into output port 4149 23 INX H Increment H register 414A 7E MOV A, M Move M content to
accumulator 414B D3 OUT 0C Load port A into output port 414D CD CALL DELAY Call DELAY address 4150 C9 RET Return to accumulator 4151 E5 DELAY PUSH H Push the register H 4152 21 LXI H,001F Load 00 1F in HL register
pair 4155 01 LXI B,FFFF Load FF FF in DE register
pair 4158 0B DCX B Decrement B register 4159 78 MOV A, B Move B content to
accumulator 415A B1 ORA C OR content of C with
accumulator 415B C2 JNZ LOOP Jump to LOOP if no zero 415E 2B DCX H Decrement H register 415F 7D MOV A, L Move L content to
accumulator
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4160 B4 ORA H OR content of H with accumulator
4161 C2 JNZ L1 Jump to L1 if no zero 4164 E1 POP H Pop the register H 4165 C9 RET Return from subroutine4166 E5 DELAY1 PUSH H Push the register H 4167 21 LXI H,001F Load 00 1F in HL register
pair 416A 01 LXI B,FFFF Load FF FF in DE register
pair 416D 0B DCX B Decrement B register 416E 78 MOV A, B Move B content to
accumulator 416F B1 ORA C OR content of C with
accumulator 4170 C2 JNZ LOOP2 Jump to LOOP2 if no zero 4173 2B DCX H Decrement H register 4174 7D MOV A, L Move L content to
accumulator 4175 B4 ORA H OR content of H with
accumulator 4176 C2 JNZ L2 Jump to L2 if no zero 4179 E1 POP H Pop the register H 417A C9 RET Return to subroutine417B 12 27 44 10
2B 92 10 9D 84 48 2E 84
DATA SEQ DB
4187 48 4B 20 49 04
DATA_E
RESULT: Thus an assembly language program to simulate the traffic light at an intersection using a
traffic light interfaces was written and implemented.
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EX.No:7 INTERFACING 8251 WITH 8085 AIM: To write a program to initiate 8251 and to check the transmission and reception of character.
APPARATUS REQUIRED: 1. 8085 Microprocessor kit
2. 8251 Interface board
3. DC regulated power supply
THEORY: The 8251 is used as a peripheral device for serial communication and is programmed by the CPU to operate using virtually any serial data transmission technique. The USART accepts data characters from the CPU in parallel format and the converts them in a continuous serial data stream of transmission. Simultaneously, it can receive serial data streams and convert them into parallel data characters for the CPU. The CPU can read the status of USART at any time. These include data transmissions errors and control signals. Prior to starting data transmission or reception, the 8251 must be loaded with a set of control words generated by the CPU. These control signals define the complete functional definition of the 8251 and must immediately follow a RESET operation. Control words should be written in to the control register of 8251. Words should be written in to the control register of 8251.words should be written in to the control register of 8251.Thesecontrol words are split into two formats. 1. MODE INSTRUCTION WORD 2. COMMAND INSTRUCTION WORD. 1. MODE INSTRUCTION WORD
This format defines the BAUD rate, character length, parity and stop bits required to work with asynchronous data communication. By selecting the appropriate BAUD factor synchronous mode, the 8251 can be operated in synchronous mode. Initializing 8251 using the Mode instructions to the following conditions.
8 bit data No parity Baud rate factor (16X) 1 stop bit Gives a mode command word of 01001110=4E(X)
EE6612 – Microprocessors and Microcontrollers Laboratory
ALGORITHM 1. Initialize timer (8253) IC 2. Move the Mode command word (4EH) to A reg. 3. Output it port address C2 4. Move the command instruction word (37H) to A reg. 5. Output it to port address C2 6. Move the data to be transfer to A reg. 7. Output it to port address C0. 8. Reset the system 9. Get the data through input port address C0. 10. Store the value in memory 11. Reset the system
PROGRAM: ADDRESS OPC
ODE LABEL
MNEMONICS
OPERAND
COMMENT
4100 MVI A, 36 Move 36 to A 4102 OUT CE Output contents of accumulator to
CE port 4104 MVI A, 0A Move 0A to accumulator 4106 OUT C8 Output contents of accumulator to
C8 port 4108 MVI A, 00 Move 00 to accumulator 410A OUT C8 Output contents of accumulator to
C8 port 410C LXI H, 4200 Store 4200 address in HL register
pair 410F MVI A, 4E Move 4E to accumulator 4111 OUT C2 Output contents of accumulator to
C2 port 4113 MVI A, 37 Move 37 to accumulator 4115 OUT C2 Output contents of accumulator to
C2 port 4117 MVI A, 41 Move 41 to accumulator 4119 OUT C0 Output contents of accumulator to
C0 port 411B RST1 4200 IN C0 Input the contents from port C0 to
accumulator 4202 STA 4150 Store the output from accumulator
to 4150 4205 RST1
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SYNCHRONOUS MODE: S2 S1 EP PEN L2 L1 B2 B1
0 1 0 1
0 0 1 1 5 BIT
6 BIT
7 BIT
8 BIT
EVEN PARITY GENERATION 0-Odd 1-Even
PARITY ENABLE 1-Enable 0-Disable
EXTERNAL SYNC DETECT 1-Sysdetect is an input 0- Sysdetect is an output
SINGLE CHARACTER SYNC 1-Single sync character 0- Double sync character
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ASYNCHRONOUS MODE: S2 S1 EP PEN L2 L1 B2 B1
0 1 0 1
0 0 1 1
Synch mode
(1 X) (16 X) (64 X)
0 1 0 1
0 0 1 1 5 BIT
6 BIT
7 BIT
8 BIT
0 1 0 1
0 0 1 1
Invalid 61BIT 1.5BIT 2 BIT
EVEN PARITY GENERATION 0-Odd 1-Even
PARITY ENABLE 1-Enable 0-Disable
EE6612 – Microprocessors and Microcontrollers Laboratory
OBSERVATION: MEMORY LOCATION INPUT DATA OUTPUT DATA
RESULT:
Thus the program to initiate 8251 was written and the transmission and reception of character was checked by interfacing 8251 with 8085.
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Ex No. 8 INTERFACING 8279 WITH 8085
AIM: To interface 8279 Programmable Keyboard Display Controller to 8085 Microprocessor. APPARATUS REQUIRED: 1. 8085 Microprocessor toolkit. 2. 8279 Interface board 3. Regulated D.C. power supply. PROGRAM: ADDRESS OPCO
DE LABEL MNEMON ICS OPERAN
D COMMENT
4100 START LXI H, 4130 Store the 16 bit address in HL pair
4103 MVI D, 0F Move 0F to D register 4105 MVI
A, 10 Move 10 to A
4107 OUT C2 Output the contents of A to C2 output port
4109 MVI A, CC Move CC to A 410B OUT
C2 Output the contents of A to
C2 output port 410D MVI A, 90 Move 90 to A 410F OUT C2 Output the contents of A to
C2 output port 4111 LOOP MOV
A, M Move content of M to A
4112 OUT C0 Output the contents of M to A
4114 CALL DELAY Call the delay address 4117 INX
H Increment H register
4118 DCR D Decrement D register
4119 JNZ LOOP Jump to specified address
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411C JMP START START Jump to START address 411F DELAY MVI B, A0 Move a to B register 4121 LOOP1 MVI C, FF Move FF to C register 4123 LOOP2 DCR
C Decrement C register
4124 JNZ LOOP 1 Jump to LOOP 1 if no zero 4127 DCR B Decrement B register 4128 JNZ LOOP 2 Jump to LOOP 2 if no zero 412B RET Pointer equal to 4130 .FF repeated eight times 4130 FF 4131 FF 4132 FF 4133 FF 4134 FF 4135 FF 4136 FF 4137 FF 4138 98 4139 68 413ª 7C 413B C8 413C 1C 413D 29 413E FF 413F FF SEGMENT DEFINITION:
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DATA BUS D7 D6 D5 D4 D3 D2 D1 D0
SEGMETS d c b a dp g f e
OBSERVATION: LETTER 7
SEGMENT DATA BUS
HEXADECIMAL
D7 D6 D5 D4 D3 D2 D1 D0
RESULT: Thus 8279 controller was interfaced with 8085 and program for rolling display was executed successfully.
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Ex.No: 9 8051 – BASIC SIMPLE PROGRAM AIM: To write an assembly language program to add, subtract, multiply and divide the given data stored at two consecutive locations using 8051 microcontroller. a. ADDITION OF TWO 8 BIT NUMBERS
Algorithm:
1. Set DPTR as pointer for data. 2. Move first data from external memory to accumulator and save it in R1 register. 3. Increment DPTR. 4. Move second data from external memory to accumulator 5. Clear R0 register to account for carry. 6. Add the content of R1 register to accumulator. 7. Check for carry. If carry is not set go to step 8. Otherwise go to next step. 8. Increment R0 register. 9. Increment DPTR and save the sum in external memory. 10. Increment DPTR, move carry to accumulator and save it in external memory. 11. Stop
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LOAD THE ADDRESS IN DPTR
MOVE THE 1ST DATA TO A – REG AND SAVE IT IN R1 REG
INCREMENT DPTR AND MOVE THE 2ND DATA TO A – REG
CLEAR R0 REGISTER
ADD A – REG WITH R1 REG TO GET SUM
If CY=1 INCREMENT R0 REG
INCREMENT DPTR AND SAVE A – REG CONTENT IN MEMORY
INCREMENT DPTR
Start
Stop
MOVE R0 TO A – REG AND THEN SAVE A – REG CONTENT IN MEMORY
Yes
No
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Label Program Comments
AHEAD:
HERE:
MOV DPTR,#4500
MOVX A,@DPTR
MOV R1,A
INC DPTR
MOVX A,@DPTR
MOV R0,#00
ADD A,R1
JNC AHEAD
INC R0
INC DPTR
MOVX A,@DPTR
INC DPTR
MOV A,R0
MOVX A,@DPTR
SJMP HERE
Load address of 1st data in DPTR
Move the 1st data to A
Save the first data in R1
Increment DPTR to point 2nd data
Load the 2nd data in A
Clear R0 for the account of carry
Get the sum in A reg
Check carry flag
If carry is set increment R0
Increment DPTR
Save the sum in external memory
Increment DPTR
Move carry to A reg
Save the carry in external memory
Remain idle in infinite loop
Observation:
Input: 4500: [Addend] 4501: [Augend]
Output: 4502: [Sum] 4503: [Carry]
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LOAD THE ADDRESS IN DPTR
MOVE THE MINUEND TO A – REG AND SAVE IT IN R1 REG
INCREMENT DPTR AND MOVE THE SUBTRAHEND TO A – REG
CLEAR R0 REGISTER AND CARRY FLAG
EXCHANGE R1 WITH A ‐ REG
If Cy=1
COMPLEMENT A AND THEN INCREMENT
INCREMENT DPTR AND SAVE A – REG CONTENT (DIFFERENCE) IN MEMORY
INCREMENT DPTR
Start
Stop
MOVE R0 TO A – REG AND THEN SAVE A – REG CONTENT (SIGN) IN MEMORY
SUBTRACT R1 FROM A ‐ REG
INCREMENT R0 REG
Yes
No
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b. SUBTRACTION OF TWO 8 BIT NUMBERS
Algorithm:
1. Set DPTR as pointer for data. 2. Move the minuend from external memory to accumulator and save it in R1 register. 3. Increment DPTR. 4. Move subtrahend from external memory to accumulator 5. Exchange the contents of R1 and A such that minuend is in A and subtrahend is in
R1 6. Clear R0 register to account for sign. 7. Clear carry flag. 8. Subtract the content of R1 register from accumulator. 9. Check for carry. If carry is not set go to step 12. Otherwise go to next step. 10. Complement the content of A – reg and increment by 1 to get 2’s complement of
result in A – reg 11. Increment R0 register. 12. Increment DPTR and save the result in external memory. 13. Increment DPTR, move R0 (sign bit) to accumulator and then save it in external
memory. 14. Stop
EE6612 – Microprocessors and Microcontrollers Laboratory
Label Program Comments
AHEAD:
HERE:
MOV DPTR,#4500
MOVX A,@DPTR
MOV R1,A
INC DPTR
MOVX A,@DPTR
XCH A,R1
MOV R0,#00
CLR C
SUBB A,R1
JNC AHEAD
CPL A
INC A
INC R0
INC DPTR
MOVX A,@DPTR
INC DPTR
MOV A,R0
MOVX A,@DPTR
SJMP HERE
Load address of minuend in DPTR
Move the minuend to A
Save the minuend in R1
Increment DPTR to point subtrahend
Load the subtrahend in A
Get minuend in A and Subtrahend in R1
Clear R0 for the account of Sign
Clear carry
Subtract R1 from A
Check Carry flag. If carry is set then
Get 2’s complement of result in A
Set R0 to indicate negative sign
Increment DPTR
Save the result in external memory
Increment DPTR
Move sign bit to A reg
Save the sign in external memory
Remain idle in infinite loop
Observation: Input: 4500: [Minuend] 4501: [Subtrahend]
Output: 4502: [Difference] 4503: [Sign Bit]
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LOAD THE ADDRESS IN DPTR
MOVE THE 1ST DATA TO A – REG AND SAVE IT IN B REG
INCREMENT DPTR AND MOVE THE 2ND DATA TO A – REG
MULTIPLY A AND B
INCREMENT DPTR
INCREMENT DPTR
MOVE B (HIGHER BYTE OF PRODUCT) TO A – REG AND THEN SAVE A – REG CONTENT IN
MEMORY
SAVE A – REG CONTENT (LOWER BYTE OF PRODUCT) IN MEMORY
Start
Stop
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c. MULTIPLICATION OF TWO 8 BIT NUMBERS
Algorithm:
1. Load address of data in DPTR 2. Move the first data from external memory to A and save in B. 3. Increment DPTR and move second data from external memory to B. 4. Perform multiplication to get the product in A and B. 5. Increment DPTR and save A ( lower byte of product) in memory 6. Increment DPTR , move B ( lower byte of product) to A and save it in memory 7. Stop
Label Program Comments
HERE:
MOV DPTR,#4500
MOVX A,@DPTR
MOV B,A
INC DPTR
MOVX A,@DPTR
MUL AB
INC DPTR
MOVX A,@DPTR
INC DPTR
MOV A,B
MOVX A,@DPTR
SJMP HERE
Load address of 1st data in DPTR
Move the 1st data to A
Save the 1st data in B
Increment DPTR to point 2nd data
Load the 2nd data in A
Get the product in A and B
Increment DPTR
Save the lower byte of result in external memory
Increment DPTR
Move the higher byte of product to A reg
Save it in external memory
Remain idle in infinite loop
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Observation
Input: 4500: [1st data] 4501: [2nd data]
Output: 4502: [Lower byte of product] 4503: [Higher byte of product]
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LOAD THE ADDRESS IN DPTR
LOAD THE DIVIDEND TO A – REG AND SAVE IT IN R0 REG
INCREMENT DPTR
LOAD THE DIVISOR IN A – REG AND SAVE IT IN B ‐ REG
INCREMENT DPTR
INCREMENT DPTR
MOVE B (REMAINDER) TO A – REG AND THEN SAVE A – REG CONTENT IN MEMORY
SAVE A – REG CONTENT (QUOTIENT) IN MEMORY
MOVE THE DIVIDEND FROM R0 TO A ‐ REG
DIVIDE A – REG CONTENT BY B – REG
Start
Stop
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d. DIVISION OF TWO 8 BIT NUMBERS
Algorithm:
1. Load address of data in DPTR 2. Move the dividend from external memory to A and save it in R0 register. 3. Increment DPTR and move the divisor from external memory to A and save it in B
reg. 4. Move the dividend from R0 to A. 5. Perform division to get quotient in A and remainder in B. 6. Increment DPTR and save quotient (content of A - reg) in memory 7. Increment DPTR. 8. Move the remainder (Content of B – reg) to A and save in memory. 9. Stop
Label Program Comments
HERE:
MOV DPTR,#4500
MOVX A,@DPTR
MOV R0,A
INC DPTR
MOVX A,@DPTR
MOV B,A
MOV A,R0
DIV AB
INC DPTR
MOVX A,@DPTR
INC DPTR
MOV A,B
MOVX A,@DPTR
SJMP HERE
Load address of dividend in DPTR
Move the dividend to A
Save the dividend in R0
Increment DPTR to point divisor
Load the divisor in A
Move the divisor to B
Move the dividend to A
Divide the content of A by B
Increment DPTR
Save the quotient in external memory
Increment DPTR
Move the remainder to A reg
Save it in external memory
Remain idle in infinite loop
EE6612 – Microprocessors and Microcontrollers Laboratory
Observation:
Input: 4500: [Dividend] 4501: [Divisor]
Output: 4502: [Quotient] 4503: [Remainder]
Result:
Thus the addition, subtraction, multiplication and division of two numbers were performed using the 8051 microcontroller.
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Ex N0. 10a SUM OF ELEMENTS IN AN ARRAY
AIM:
To find the sum of elements in an array.
ALGORITHM:
1. Load the array in the consecutive memory location and initialize the
memory pointer with the starting address.
2. Load the total number of elements in a separate register as a counter.
3. Clear the accumulator.
4. Load the other register with the value of the memory pointer.
5. Add the register with the accumulator.
6. Check for carry, if exist, increment the carry register by 1. otherwise,
continue
7. Decrement the counter and if it reaches 0, stop. Otherwise increment the
memory pointer by 1 and go to step 4.
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Yes
Yes
[A] [DPTR] [R0] [A]
[DPTR] [4200H], Clear B, R1 and CY
[A] [DPTR+1]
[A] [A] +[B] [A] [B]
Is Cy=1
[R1] [R1]+1
[4500] [A] [B] [4501] [A] [R1]
START
[R0] [R0]-1
IS [R0] = 0?
STOP
No
No
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM:
Label Program Comments
AGAIN
NC
HERE
MOV DPTR, #4200
MOVX A, @DPTR
MOV R0, A
MOV B, #00
MOV R1, B
CLR C
INC DPTR
MOVX A, @DPTR
ADD A, B
MOV B, A
JNC NC
INC R1
DJNZ R0,AGAIN
MOV DPTR, #4500
MOV A, B
MOVX @DPTR, A
INC DPTR
MOV A, R1
MOVX @DPTR, A
SJMP HERE
Load 4200 to DPTR, get array size
Copy array size value to A
Move contents of A to R0
Clear B, R1 & Carry Flag
Get value from data pointer
Sum of two numbers
If no carry jump to NC
Else increment R1
Decrement size of array, if not zero fetch data from
DPTR and add to the resultant value
Store the result in 4500 memory locations
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OBSERVATION:
INPUT OUTPUT
4200 4500
4201
4202
4501
4203
RESULT:
The sum of elements in an array is calculated.
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Exp. No 10(b) 8051 – Check Odd or Even using Call Option AIM:
To Check whether given number is Odd or Even using Call Option.
ALGORITHM:
1. Start
2. Move the data to DPTR
3. Move the data to accumulator
4. Call check function whether given number is odd or even
5. Increment DPTR
6. Resultant value stored in DPTR-4201
7. Halt
Check Function
8. Rotate right through carry
9. If carry copy 00 to B reg (odd number)
10. Else copy EE to B reg (even number)
11. return
EE6612 – Microprocessors and Microcontrollers Laboratory
[DPTR] [4200H] [A] [DPTR]
[DPTR] [DPTR] +1 [A] [B]
[DPTR] [A]
START
STOP
Check Even & odd
No Yes Is CY=1
Rotate the A right through carry
[B] 00H, for odd [B] EEH, for even
Check Even & odd
Return
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM:
Label Program Comments
HERE
CHECK_EV_OD
L1
MOV DPTR, #4200
MOVX A, @DPTR
CALL CHECK_EV_OD
INC DPTR
MOV A,B
MOVX @DPTR, A
SJMP HERE
RRC A
JC L1
MOV B,#0EEH
MOV B,#00H
RET
Load 4200 to DPTR, get a number
Copy value to A
Call check function whether given number is
odd or even
Resultant value stored in DPTR-4201
Rotate right through carry
If carry copy 00 to B reg (odd number)
Else copy EE to B reg (even number)
OBSERVATION:
INPUT OUTPUT
4200 4201
RESULT:
Thus the given number is either even or odd has been found using 8051 microcontroller.
EE6612 – Microprocessors and Microcontrollers Laboratory
11 INTERFACING A/D & D/A CONVERTER WITH 8051 a. ADC INTERFACING WITH 8051 APPARATUS REQUIRED:
SL.NO ITEM SPECIFICATION QUANTITY 1 Microcontroller kit 8051,Vi Microsystems 1 2 Power supply +5 V dc 1 3 ADC Interface board Vi Microsystems 1
PROBLEM STATEMENT: To program starts from memory location 4100H. The program is executed for various values of analog voltage which are set with the help of a potentiometer. The LED display is verified with the digital value that is stored in the memory location 4150H. THEORY: An ADC usually has two additional control lines: the SOC input to tell the ADC when to start the conversion and the EOC output to announce when the conversion is complete. The following program initiates the conversion process, checks the EOC pin of ADC 0419 as to whether the conversion is over and then inputs the data to the processor. It also instructs the processor to store the converted digital data at RAM 4200H. ALGORITHM:
1. Select the channel and latch the address. 2. Send the start conversion pulse. 3. Read EOC signal. 4. If EOC =1 continue else go to step (3) 5. Read the digital output. 6. Store it in a memory location.
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM:
Label Program Comments
WAIT
HERE
MOV DPTR, #FFC8
MOV A,#10
MOVX @DPTR, A
MOV A,#18
MOVX @DPTR, A
MOV DPTR, #FFD0
MOV A,#01
MOVX @DPTR, A
MOV A,#00
MOVX @DPTR, A
MOV DPTR, #FFD8
MOVX A,@DPTR
JNB E0,WAIT
MOV DPTR,#FFC0
MOVX A,@DPTR
MOV DPTR,#4150
MOVX @DPTR, A
SJMP HERE
Select Channel 0 and make ALE Low
make ALE High
SOC signal High
SOC signal low
Check for EOC
Read ADC data
Store the data in memory location
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ADC- CIRCUIT:
SOC JUMPER SELECTION:
J2: SOC Jumper selection
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J5: Channel selection OBSERVATION
ANALOG VOLTAGE DIGITAL DATA ON LED DISPLAY
HEX CODE IN LOCATION 4150
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(b) INTERFACING D/A CONVERTER WITH 8051 APPARATUS REQUIRED:
SL.NO ITEM SPECIFICATION QUANTITY 1 Microprocessor kit 4185,Vi Microsystems 1 2 Power supply +5 V dc 1 3 DAC Interface board Vi Microsystems 1
THEORY: SOFTWARE EXAMPLES After going through the software examples you can learn how to control the DAC using 8051 and generate sine wave, saw tooth wave etc by means of software. ALGORITHM: (a) SQUARE WAVE GENERATION:
1. Load the initial value (00) to Accumulator and move it to DAC. 2. Call the delay program 3. Load the final value (FF) to accumulator and move it to DAC. 4. Call the delay program. 5. Repeat steps 2 to 5.
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OBSERVATION: WAVE FORMS AMPLITUDE TIME PERIOD Square waveform Saw tooth waveform Triangular waveform
PROGRAM: The basic idea behind the generation of waveforms is the continuous generation of
Analog output of DAC. With 00(HEX) as input to DAC2, the analog output is -5V. Similarly, with FF (Hex) as input, the output is +5V. Outputting digital data 00 and FF at regular intervals, to DAC2, results in a square wave of amplitude I5 Volts.
ADDRESS LABEL MNEMON ICS OPCODE OPERAND COMMENT MOV DPTR,#FFC8 START MOV A,#00 MOVX @DPTR,A LCALL DELAY MOV A,# FF MOVX @DPTR,A LCALL DELAY LJMP START DELAY MOV R1,#05 LOO[P MOV R2,#FF DJNZ R2,HERE DJNZ R1,LOOP RET SJMP START
Execute the program and using a CRO, verify that the waveform at the DAC2 output is a square-wave. Modify the frequency of the square-wave, by varying the time delay.
(b) SAW TOOTH GENERATION 1. Load the initial value (00) to Accumulator 2. Move the accumulator content to DAC. 3. Increment the accumulator content by 1. 4. Repeat steps 3 and 4. Output digital data from 00 to FF constant steps of 01 to DAC1 repeat this sequence again and again. As a result a saw – tooth wave will be generated at DAC1 output.
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM: ADDRESS LABEL MNEMON ICS OPCODE OPERAND COMMENT MOV DPTR,#FFC0 MOV A,#00 LOOP MOVX @DPTR,A INC A SJMP LOOP
(c) TRIANGULAR WAVE GENERATION 1. Load the initial value (00) to Accumulator. 2. Move the accumulator content to DAC 3. Increment the accumulator content by 1. 4. If accumulator content is zero proceed to next step. Else go to step 3. 5. Load value (FF) to accumulator. 6. Move the accumulator content to DAC. 7. Decrement the accumulator content by 1. 8. If accumulator content is zero go to step 2. Else go to step 2. The following program will generate a triangular wave at DAC2 output. The program is self explanatory. ADDRESS LABEL MNEMON ICS OPCODE OPERAND COMMENT MOV DPTR,#FFC8 START MOV A,#00 LOOP1 MOVX @DPTR,A INC A JNZ LOOP1 MOV A,#FF LOOP2 MOVX @DPTR,A DEC A JNZ LOOP2 LJMP START
OBSERVATION: WAVE FORMS AMPLITUDE TIME PERIOD Square waveform Saw tooth waveform Triangular waveform
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Result: Thus the square, triangular and saw tooth wave form were generated by interfacing DAC with 8051 trainer kit.
EE6612 – Microprocessors and Microcontrollers Laboratory
Ex.No:15 INTERFACING 8253 TIMER WITH 8085 AIM:
To interface 8253 Interface board to 8085 microprocessor to demonstrate the generation of square wave.
APPARATUS REQUIRED:
1. 8085 microprocessor kit
2. 8253 Interface board
3. DC regulated power supply
4. CRO.
.
PROGRAM: Address Opcodes Label Mnemonic Operands Comments 4100 3E 36 START: MVI A, 36 Channel 0 in mode 3 4102 D3 CE OUT CE Send Mode Control word 4104 3E 0A MVI A, 0A LSB of count 4106 D3 C8 OUT C8 Write count to register 4108 3E 00 MVI A, 00 MSB of count 410A D3 C8 OUT C8 Write count to register 410C 76 HLT
Set the jumper, so that the clock 0 of 8253 is given a square wave of frequency 1.5 MHz. This program divides this PCLK by 10 and thus the output at channel 0 is 150 KHz. Vary the frequency by varying the count. Here the maximum count is FFFF H. So, the square wave will remain high for 7FFF H counts and remain low for 7FFF H counts. Thus with the input clock frequency of 1.5 MHz, which corresponds to a period of 0.067 microseconds, the resulting square wave has an ON time of 0.02184 microseconds and an OFF time of 0.02184 microseconds. To increase the time period of square wave, set the jumpers such that CLK2 of 8253 is connected to OUT 0. Using the above-mentioned program, output a square wave of frequency 150 KHz at channel 0. Now this is the clock to channel 2.
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CONTROL WORD: SC1 SC2 RW1 RW0 M2 M1 M0 BCD
SC-SELECT COUNTER: SC1 SC0 SELECT COUNTER
0 0 Select counter 0
0 1 Select counter 1
1 0 Select counter 2
1 1 Read back command
M-MODE: M2 M1 M0 MODE 0 0 0 Mode 0 0 0 1 Mode 1 X 1 0 Mode 2 X 1 1 Mode 3 1 0 0 Mode 4 1 0 1 Mode 5 READ/WRITE: RW1 RW0
0 0 Counter latch command
0 1 R/W least significant bit only
1 0 R/W most significant bit only
1 1 R/W least sig first and most sig byte
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BCD:
0 Binary counter 16-bit
1 Binary coded decimal counter
Result: Thus the 8253 has been interfaced to 8085 μp and with different modes of 8253 have been studied.
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Ex.No:15 STEPPER MOTOR INTERFACING WITH 8051 AIM:
To interface a stepper motor with 8051 microcontroller and operate it. THEORY: A motor in which the rotor is able to assume only discrete stationary angular position is a stepper motor. The rotary motion occurs in a step-wise manner from one equilibrium position to the next. Stepper Motors are used very wisely in position control systems like printers, disk drives, process control machine tools, etc. The basic two-phase stepper motor consists of two pairs of stator poles. Each of the four poles has its own winding. The excitation of any one winding generates a North Pole. A South Pole gets induced at the diametrically opposite side. The rotor magnetic system has two end faces. It is a permanent magnet with one face as South Pole and the other as North Pole. The Stepper Motor windings A1, A2, B1, B2 are cyclically excited with a DC current to run the motor in clockwise direction. By reversing the phase sequence as A1, B2, A2, B1, anticlockwise stepping can be obtained. 2-PHASE SWITCHING SCHEME: In this scheme, any two adjacent stator windings are energized. The switching scheme is shown in the table given below. This scheme produces more torque.
ANTICLOCKWISE CLOCKWISE STEP A1 A2 B1 B2 DATA STEP A1 A2 B1 B2 DATA
1 1 0 0 1 9h 1 1 0 1 0 Ah 2 0 1 0 1 5h 2 0 1 1 0 6h 3 0 1 1 0 6h 3 0 1 0 1 5h 4 1 0 1 0 Ah 4 1 0 0 1 9h
ADDRESS DECODING LOGIC:
The 74138 chip is used for generating the address decoding logic to generate the device select pulses, CS1 & CS2 for selecting the IC 74175.The 74175 latches the data bus to the stepper motor driving circuitry. Stepper Motor requires logic signals of relatively high power. Therefore, the interface circuitry that generates the driving pulses use silicon Darlington pair transistors. The inputs for the interface circuit are TTL pulses generated under software control using the Microcontroller Kit. The TTL levels of pulse sequence from the data bus are translated to high voltage output pulses using a buffer 7407 with open collector.
EE6612 – Microprocessors and Microcontrollers Laboratory
BLOCK DIAGRAM:
REPRESENTATION:
8051
MICROCONTROLLER
8255
DRIVER CIRCUIT
STEPPER MOTOR
EE6612 – Microprocessors and Microcontrollers Laboratory
PROGRAM :
Address OPCODES Label MNEMONICS OPERAND Comments
ORG 4100h
4100
START MOV DPTR, #TABLE Load the start address of switching scheme data TABLE into Data Pointer (DPTR)
4103 MOV R0, #04 Load the count in R0 4105 LOOP: MOVX A, @DPTR Load the number in
TABLE into A 4106 PUSH DPH Push DPTR value to
Stack 4108 PUSH DPL 410A MOV DPTR, #0FFC0h Load the Motor port
address into DPTR 410D
MOVX @DPTR, A Send the value in A to
stepper Motor port address
410E MOV R4, #0FFh Delay loop to cause a specific amount of time delay before next data item is sent to the Motor
4110 DELAY:
MOV R5, #0FFh
4112 DELAY1:
DJNZ R5, DELAY1
4114 DJNZ R4, DELAY 4116 POP DPL POP back DPTR value
from Stack 4118 POP DPH 411A
INC DPTR Increment DPTR to
point to next item in the table
411B DJNZ R0, LOOP Decrement R0, if not zero repeat the loop
411D
SJMP START Short jump to Start of the program to make the motor rotate continuously
411F
TABLE:
DB 09 05 06 0Ah Values as per two-phase switching scheme
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PROCEDURE: 1. Enter the above program starting from location 4100.and execute the same. 2. The stepper motor rotates. 3. Varying the count at R4 and R5 can vary the speed. 4. Entering the data in the look-up TABLE in the reverse order can vary direction of rotation.
RESULT: Thus a stepper motor was interfaced with 8051 and run in forward and reverse directions at various speeds.